Compact vacuum pump

ABSTRACT

A vacuum pump capable of pumping solid, liquid and gas, or any combination thereof, including a drive ( 40 ) and a manually disengageable pumping system connected thereto. The pumping system is composed of a two- or three-chambered canister ( 1, 18, 21 ) within which solids, liquids, and gases can be separated from one another. A highly flexible diaphragm ( 24 ), attached to the canister and sealed against it circumferentially, facilitates this separation, when reciprocating and pumping. The components of the pumping system are designed to be disposable, and the two- or three-chambered canister provides for a highly efficient pumping system that is significantly smaller in size than those previously known. The pump is particularly useful for medical applications.

The present invention relates to a vacuum pump, especially useful in thefield of medicine. More specifically, the pump disclosed herein includesa drive and a disposable pumping system that can be easily disengagedfrom the drive after use to allow for easy disposal of all pumpcomponents which come into contact with the matter being suctioned,together with the contained matter. The pump is not limited in thevolume of matter it is capable of suctioned while maintaininguninterrupted vacuum pressure. During medical surgery or emergencyairway clearing body fluids, such as blood or emesis, are suctioned.Vacuum pumps are utilized to generate vacuum inside a suction canisterinto which the body fluids are drawn through a tube, called a “suctioncatheter.” Conventional vacuum pumps, also termed “aspirators” inmedicine, contain rigid vacuum canisters into which the suctioned fluidsare collected that maintain their shape and stiffness under high vacuumpressure. Some suction canisters are disposable and others can beremoved for cleaning, disinfection, and re-use.

Aspirators of the type described above are characterized by a number ofdisadvantages, including the following:

-   1. When a large volume of fluid is collected, the suction canisters    have to be relatively large in volume. Most commonly a canister of    up to five liters in volume is used. Large canisters slow the vacuum    rise rate because of the large air volume to be removed from the    canister before a vacuum is created in the canister strong enough to    draw the suctioned matter.-   2. Since the air in the suction canister is drawn through the pump,    it is very difficult to prevent contamination of the non-disposable    pump components, such as the diaphragm, valves, cylinder or piston,    even when the suction canister is disposed of after use.    Contaminated pumps are a health hazard as the air flowing through    them is exhausted to the atmosphere.-   3. Aspirators are used for drawing body fluids and emesis, which may    contain solids. Air is also drawn into the pump, during aspiration.    Vacuum pumps are generally efficient in pumping either air or    fluids, but most pumps are inefficient in pumping all three types of    matter.

Thus, conventional vacuum devices are large, bulky, costly andinefficient in performing their function.

In the present invention the term “pumping system” generally refers to asystem having the following components: a suction canister, a suctioninlet, a waste outlet, and integral means for creating suction. The term“disposable vacuum pump” generally refers to a pump in which allcomponents other than the drive are inexpensive, and therefore may bedisposed of. One wishing to re-use the disposable components (or usesimilar, non-disposable components) may, however, do so. The term“drive” generally refers to a pump component included of an electricmotor, or to other means by which a pump piston, or a diaphragm, may becaused to reciprocate while contained within a housing. The term “bodyfluids” refers to blood, emesis or mucus. The term “three types ofmatter,” “three types of media,” and “three states of matter” refer toliquid, solid and gas. The terms “matter,” “media,” and “material” areused interchangeably to refer to the material being suctioned.

Embodiments of the invention may provide an improved vacuum pump capableof pumping air or gas, liquid and solids, and capable of separating thethree types of matter to allow efficient pumping while collecting theliquid in a low cost bag.

Further embodiments may provide a pump in which all components that comein contact with body matter, or any other pumped media, can be easilydisconnected and removed from the pump's drive means to be sterilized ordisposed of. This leaves the non-disposable drive free fromcontamination. In prior-art pumps that have disposable canisters, thesuctioned air is drawn through the pump, bringing the inside of the pumpin contact with air that may be contaminated. The inside of the pump istraditionally not accessible for cleaning.

Embodiments of the present invention may further provide a vacuum pumpwhich is extremely fast in generating a high vacuum or suction pressureyet do so with a relatively small vacuum canister and a low capacitypump.

It is further desirable to provide a physically compact vacuum pump withperformance and capacity that are independent of its dimensions and aresignificantly higher than those of physically larger vacuum pumps. Inaddition, it is desirable to provide a vacuum pump which generatesuninterrupted vacuum, independent of the volume of the vacuum canisterthat does not fill up as do conventional vacuum canisters.

The vacuum pump includes a drive and a disposable pumping systemconnected to this drive and adapted to be manually disengaged therefrom,wherein the disposable pumping system includes:

-   (a) a three-chambered canister, wherein an inlet leads into the    first chamber, and the first chamber has means for retaining solids    and preventing their passage from the first chamber to the second    chamber; and the second chamber has a one-way valve at its exit, the    valve allowing passage of liquid and gas out of the second chamber;    and the third chamber has an outlet for the discharge of air, and an    additional outlet for the discharge of liquid; and the third chamber    further has a one-way valve at its inlet allowing entry of liquid    and gas through the valve while preventing exit of matter through    the valve;-   (b) a highly flexible diaphragm, attached to the three-chambered    canister, sealing against it circumferentially, wherein the flexible    diaphragm is attached to a partition with the three-chambered    canister, in which the valves are installed;-   (c) a drive member attached to the diaphragm, wherein reciprocation    of the drive member induces reciprocation of the diaphragm; and-   (d) means for mounting and engaging the disposable pumping system to    the housing of a drive, wherein the means are capable of    simultaneously coupling the pump drive member to the drive.

The drive is coupled to the drive member, and the drive includes anelectric motor rotating a crank, the crank being connected toreciprocating means, in such a way that activation of the drive inducesreciprocation of the crank and of the drive member. The pumping systemis capable of being attached or detached from the drive in a rapid andfacile manner (in the preferred embodiment, accomplished by a single,simple, wrist twist motion).

According to preferred embodiment of the present invention, thethree-chambered canister has a volume of approximately 100 cc.

Further according to a preferred embodiment of the present invention,the pump includes a vacuum port outlet present in the second chamber,the outlet connected by tubing to an external vacuum gauge for thepurpose of monitoring the pressure inside the first and second chambers.

Additionally, according to a preferred embodiment of the presentinvention, the means for retaining solids in the first chamber areincluded of a sieve.

Moreover, according to preferred embodiment of the present invention,the highly flexible diaphragm is capable of yielding or stretching whenlarge quantities of fluid are contained within it. When subjected tohigh loads, the diaphragm is capable of stretching to effectivelyreciprocate only a fraction of its area (such as 50%) while theremainder of its surface remains stationary.

Still further, according to preferred embodiments of the presentinvention, the vacuum pump additionally includes means for sealing thethree-chambered canister and preventing leakage of air or materials intoor out of the canister, as well as further preventing loss of vacuum infirst and second chambers.

According to embodiments of the present invention, the pump additionallyincludes a disposable waste container for collection of dischargedliquid that is attached to the liquid outlet of the third chamber. In apreferred embodiment, the disposable waste container is a waste bag,having any appropriate size. In some preferred embodiments, the capacityof the waste bag is between 500 cc and 5 liters. The waste-collectionbag is a low cost waste container, at ambient pressure, which is easilydisposed of along with the body fluids it contains, together with thepumping system.

Furthermore, according to the preferred embodiment of the presentinvention, the means for mounting and engaging the pumping system to thedrive housing include a mounting base protruding from the lower portionof the three-chambered canister, the mounting base adapted for matingand attaching to the drive housing. In the preferred embodiment,twisting of the mounting base against the drive housing or matingportion thereof couples the two physically.

Still further yet, according to the preferred embodiment of the presentinvention, the drive rotates a crank, and a reciprocating rod receptacleis connected to the crank, and the rod receptacle is adapted to matewith the drive member. In the preferred embodiment, a lock clip securesthe drive member to the rod receptacle. Coupling the mounting base tothe drive housing is affected simultaneously with the securing of thedrive member to the rod receptacle, in a single operation.

Additionally, the pumping system and the drive may be portable and maybe operated on battery power.

Moreover, the pumping system additionally includes means for sealing thepumping system, for facilitating disposal of the pumping system, withall pumped matter contained. Further according to preferred embodimentsof the present invention, the pump is capable of generating continuousflow of matter therethrough, while maintaining uninterrupted vacuumpressure.

The pump may be capable of generating a vacuum pressure of approximately650 mm of Mercury as measured in the first and second chambers.

Additionally, in a preferred embodiment, the pump further includessuction catheter tubing attached to the inlet present in the firstchamber, allowing entry of matter into the three-chambered canister.

Unlike common diaphragm pumps, the diaphragm in this invention isflexible and not restrained by a rigid piston. The flexibility of thediaphragm allows it to stretch and conform to the pumped matter,irrespective of the reciprocal motion of the rigid drive member. Thus,when the diaphragm encounters resistance it stretches and yields,allowing uninterrupted motion of the reciprocating drive member.

The three-chambered canister, the diaphragm and the one-way valvesadvantageously include an integral pumping system that can easily beattached to a drive that causes the drive member to reciprocate. Such adrive, as described, may be an electric motor, whose output shaft has acrank to which the drive member is connected. The electric motor willthus, when powered, affect pumping from one chamber of the canister tothe other. The pumping system can easily be disengaged from the driveafter use, and be sterilized or disposed of. The ability to completelyseparate the heart of the pump and its associated chambers and tubingconduits from the drive motor allows disposal or sterilization of allpump components that come in contact with pumped matter. It would beobvious to those skilled in the art that means other than an electricmotor may be utilized to induce the reciprocal motion of the drivemember.

The three-chambered canister is constructed in a manner such that thesolids entering the chamber are trapped and prevented from enteringfurther into the pump and affecting its performance by blocking thevalves and tubing. It would be obvious to those skilled in the art thatwhen the pumped matter is not likely to include solids, there would beno need to prevent them from reaching the pump's one-way valves, andthus the pumping system hereby described would function equally wellwithout the first chamber. A pump having only two chambers, to be usedin such case, is thus described below as well. Additionally, the pumpedair is separated from the fluid and released to the atmosphere so thatliquid, and not air, is collected in the waste bag, thereby utilizingthe volume of the waste bag efficiently. Thus, the capacity of the pumpto suck or collect fluids is not limited by the size of the chamber intowhich the fluid is drawn, and even a small chamber can be utilized topump large volumes of fluid, limited only by the capacity of the wastebag. This is in contrast to pumps of the prior art in which the canisteror chamber size limits the amount of matter that may be suctioned, andwhen large canisters are used to overcome this limitation evacuating thelarge canister by the pump then becomes a slow process.

The present invention can be utilized in the field of medicine, toaspirate body fluids, emesis and mucous; however, the scope of theinvention is not limited to medical use alone, and the vacuum pump maybe utilized in other fields as well. An important feature of the pump isthe ability to easily and economically remove and replace all componentsthat come in contact with the materials being pumped, thus preventingany harmful contamination. The pump can therefore find application inthe field of chemistry as well, where prior art pumps are difficult toclean after use.

In addition, there is provided in an alternative aspect of the presentinvention a vacuum pump for the pumping of liquid and gas (preferablynot for use in pumping of solids), including a drive, and a manuallydisengageable disposable pumping system connected to the drive, whereinthe disposable pumping system includes:

-   a) a dual-chambered canister, wherein the first chamber has an inlet    and a one-way valve at the exit of the first chamber, the valve    allowing passage of liquid and gas out of the first chamber; and the    second chamber has an outlet for the discharge of air, and an    additional outlet for the discharge of liquid; and the second    chamber is further connected via a one-valve, allowing entrance of    liquid or gas through the valve, while preventing exit of liquid or    gas through the valve;-   b) a highly flexible diaphragm, attached to the dual-chambered    canister sealing against it circumferentially, wherein the flexible    diaphragm is attached to a partition with the dual-chambered    canister in which the valves are installed;-   c) a drive member attached to the diaphragm, reciprocation of the    drive member inducing reciprocation of the diaphragm; and-   d) means for mounting and engaging the disposable pumping system to    the housing of a drive, wherein the means are capable of    simultaneously coupling the drive member to the drive.

In the vacuum pump the drive is coupled to the pumping system so thatactivation of the drive induces reciprocation of the flexible diaphragm,and the pumping system is capable of being attached or detached from thedrive in a rapid and facile manner.

It will be clear to those skilled in the art that while the preferredembodiment of the invention includes several features, partialapplication of the disclosed features of the invention does not limitthe scope of the invention. For instance, the diaphragm may besubstituted by a piston for pumping, the discharge port may function inthe absence of the waste bag and the liquid and gas outlets may becombined into a single outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, embodiments of it will nowbe described by way of example, with reference to the accompanyingdrawings in which:

FIG. 1 a cross-sectional view of a preferred disposable vacuum pumphaving a three-chambered canister connected to a waste bag, wherein thesuction is created by reciprocating a diaphragm by an electric motordrive;

FIG. 2 is a cross-sectional view of the “pumping system” disengaged fromthe “drive”, to be dis of as one integral unit;

FIG. 3 is a view of a mounting base, with a bayonet arrangement forquick-twist engagement and disengagement of the disposable components;and

FIG. 4 is a cross-sectional view of the locking mechanism, utilized toattach the pump drive member to the receptacle rod of the electricmotor.

DETAILED DESCRIPTION OF THE INVENTION

It is appreciated that the detailed description that follows is intendedonly to illustrate certain preferred embodiments of the presentinvention. It is in no way intended to limit the scope of the invention,as set out in the claims.

Referring now to FIG. 1, there is provided a vacuum pump containing athree-chambered canister 10, which is employed for the performance ofseveral different functions. The three-chambered canister 10 has aninlet 11 in its first chamber 1. A suction tube catheter 12 is connectedto the inlet 11. In the second chamber 18 a vacuum outlet port 13 isconnected to a vacuum gauge 14. In the third chamber 21 an air dischargeoutlet 15 is present, which is open to the atmosphere. The first chamber1 contains a sieve 16, utilized to prevent solids 17 from entering thesecond chamber 18, also termed the “liquid chamber.” Two one-wayumbrella valves 19 and 20 are present in the bottom of the secondchamber 18 and the third chamber 21, respectively. The third chamber 21is at ambient pressure, and has a liquid outlet 22. To the bottom of thethree-chambered canister 10 there is attached a mounting base 23, usedto mount the canister and its associated tubing 12 onto the drivehousing 40 or on a docking means connected to the drive housing. Themounting base 23 is also utilized to secure a diaphragm 24 to theunderside of the three-chambered canister 10. The diaphragm 24 has anintegral rod-shaped drive member 25, which is inserted into acorresponding cavity in a receptacle rod 26, pivotally attached to motor39, via a crank 27 coupled to a bearing 28. Upon activation of the motor39, the crank 28 is rotated by motor 39, which reciprocates thereceptacle rod 26, causing the diaphragm 24 to increase and decrease thevolume of the cavity 29 that it forms. This creates a vacuum therein,capable of drawing towards it, and thus pumping, air or fluid thatpasses through the one-way umbrella valves 19 and 20.

While the preferred embodiment describes a motor-crank combination asthe means by which to reciprocate diaphragm 24, it would be apparentthat other drive means may be used to create the reciprocal movement ofthe diaphragm.

Air, liquid and solids may enter the three-chambered canister 10 througha suction tube 12, which may, by way of example, be inserted into apatient's mouth for the removal of emesis. The three states of matterbeing pumped enter the three-chambered canister 10 through the inlet 11.Solids 17 are prevented from moving further than the first chamber 1 bymeans of sieve 16. Liquids and air enter the second chamber (liquidchamber) 18, which is under vacuum when diaphragm 24 reciprocates,driving them past one-way umbrella valve 20 into the third chamber 21.The vacuum level in liquid chamber 18 is monitored by a vacuum gauge 14,connected to the vacuum outlet port 13 via a conduit 30. The air andliquid entering the third chamber 21 are separated, whereupon the liquidis drained into waste bag 31 through a drain tube 32, and the air isdriven out to atmosphere through an air discharge outlet 15.

From the description above, it is clear that the three-chamberedcanister 10 is the heart of the pump, to which the diaphragm 24 isattached to perform the pump function together with the one-way umbrellavalves 19 and 20. Out of the three-chambers that make up thethree-chambered canister, only one, the liquid chamber 18, is undervacuum. The three-chambered canister is partitioned by the sieve 16; thefirst chamber 1 and the third chamber 21 are essentially at ambientpressure.

The pump hereby described is distinct in its capability to suck liquid,solids and air or any mixture of the three, and to separate each of thethree matter types into their respective destinations. The three typesof matter are separated in order to prevent clogging of the pump bysuctioned solids, and in order to collect only fluid for disposal, andnot gas, thus minimizing the volume of the waste material for disposal,and of the canister that holds this waste material. It is also ofparticular importance to note that air and liquid can be pumped throughthe pump continuously at any volume, limited only by the volume of thewaste bag 31 to contain the pumped liquids.

The pump's ability to pump air and liquid is unlike conventional pumpsthat are efficient in pumping only one type of matter, and is enhancedby the flexibility of the diaphragm 24. Unlike conventional pumpdiaphragms, which are rigidified by a piston or ribbing to prevent themfrom excessive flexing which reduces displacement, the diaphragm 24described in this invention is particularly flexible so it can yieldwhen encountering heavy loads such as those present when pumping liquid.This diaphragm flexibility also provides an additional substantialadvantage: when the vacuum in pumping volume 29 is high the diaphragm 24stretches to allow the reciprocation of the receptacle rod 26 to occurat minimal burden to the “drive,” which in the preferred embodimentincludes an electric motor 39.

In order to obtain high vacuum levels it is necessary to extract all airfrom pumping cavity 29 when the diaphragm 24 is at its upper travelextremity, as illustrated in FIG. 2. This function, in a conventionalvacuum pump, will cause damage to the pump when liquid or solids enterthe pumping chamber, as they cannot be expelled through the pump'soutlet valve fast enough. In the disclosed invention, the flexibility ofthe diaphragm 24 will allow it to yield, or bulge, when encounteringresistance as a result of liquid or solid presence, preventing excessiveforces and the ensuing damage.

An additional important function of the flexibility of diaphragm 24 isits ability to stretch and yield, so that when the vacuum level in thepumping cavity 29 is high, only a smaller effective area of diaphragm 24reciprocates, and stretches, requiring less power from motor 39 toeffect reciprocation.

In FIG. 2, drive housing 40 that contains the motor 39, crank 27 andreciprocating receptacle rod 26, is shown disengaged from all otherparts since the drive will be re-used while all other parts, which havedirectly contacted the matter being pumped, are slated for disposal andare termed the “disposable pumping system.” The disposable pumpingsystem, essentially including the canister, the diaphragm, associatedvalves, the disposable waste bag, and associated tubing, are shown inFIG. 2 after all outlets have been sealed for disposal. The suction tube12 is plugged with a plug 33 to prevent any liquid from leaking out ofit. The conduit 30 is disengaged from the vacuum gauge 14 (FIG. 1) andattached to the air discharge outlet 15, sealing all possible leak pathsfrom three-chambered canister 10.

It will be appreciated by persons skilled in the art that the drive 40,which is the only non-disposable hardware in the preferred embodiment,does not come into contact with any of the pumped media. This is unlikeconventional aspirators or suction pumps that pass the suctioned airthrough them and may thus be contaminated by infectious air.

The method and means for attachment and mounting of the disposablepumping system to drive 40 is illustrated in FIGS. 2 and 3, whereby themounting base 23 is placed on top of retainers 41 as shown in FIG. 2.The retainers 41 protrude from a shelf- or step-like part of the drive40 and have large mushroom-shaped heads, which pass through largeropenings 42 in a flange of the base 23, seen also in FIG. 3. When thethree-chambered canister 10 is rotated clockwise with its mounting base23, the large heads of the retainers 41 engage slots 45 (FIG. 3),attaching the mounting base 23 to the drive 40 in a bayonet-typefastening action using a 45-degree twist. This action is similar toattaching a cap to a glass jar. The drive member 25, shown in FIGS. 1and 2, is inserted into the receptacle rod 26 simultaneously with theattachment of the mounting base 23 to drive housing 40.

Referring to FIG. 4, a spring-loaded lock-clip 46 keys and locks thedrive member 25 to the receptacle rod 26, when the lock clip engagespre-aligned slots 48 present in the drive member 25 and the receptaclerod 26. The disengagement of the mounting base 23 from the drive 40 iseffected, simultaneously with disengagement of the drive member 25 fromthe receptacle rod 26, when both are rotated counterclockwise, by drivemember 25 pushing lock clip 46 out of its slot 47, as illustrated inFIG. 4, eliminating the keying between drive member 25 and receptaclerod 26. This action is similar to the removal of a cap from a jar bytwisting counterclockwise and lifting.

While only one form of engagement of canister 10 to drive 40 wasdescribed in the preferred embodiment of this invention, it would beclear to those skilled in the art that other similar methods for quickfastening of these parts can be utilized effectively.

The above-described method of engagement has, however, an importantfeature that should be noted. Since the receptacle rod 26 may be at itslower position at the time when the drive member 25 is inserted into it,slots 47 and 48 may come into alignment only when motor 39 is poweredand crank 27 (FIGS. 1 and 2) raises receptacle rod 26 allowing lock clip46 to key slots 47 and 48. Thus, the insertion of drive member 25 intoreceptacle rod 26 enables engagement, rather than fastening the twotogether.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been shown and describedhereinabove, merely by way of example. Rather, the scope of the presentinvention is limited solely by the claims, which follow:

1. Pumping apparatus, comprising a drive unit with a driving element,and a pump unit attachable to and detachable from said drive unit, saidpump unit including a pumping chamber and a pump member with areciprocable drive member, said pump member defining part of saidpumping chamber, said pumping chamber being adapted to expand andcontract for pumping by two-way forced reciprocation of said pump memberunder action of said reciprocable drive member; wherein said pump unitand said drive unit comprise a means for attaching said pump unit tosaid drive unit such as to bring said drive member and said drivingelement to a position wherein said drive member is generally coaxialwith said driving element, providing, during operation of said driveunit, for their engagement and reciprocation of said drive member bymeans of said driving element.
 2. The apparatus according to claim 1,wherein said drive unit comprises first attachment means and said pumpunit comprises second attachment means, the two attachment meansallowing said attaching of the pump unit to the drive unit by a simplemanipulation without tools.
 3. The apparatus according to claim 2,wherein said pump unit and said drive unit are constructed so that saidfirst and second attachment means provide detachment of said drive unitfrom said pump unit by a manipulation including at the most manualunfastening without tools and one detaching motion, and the samedetaching motion disengages said drive member from said driving element.4. The apparatus according to claim 2, wherein said pump unit is made ofmaterials suitable for its usage as a disposable unit.
 5. The apparatusaccording to claim 4, wherein said pump unit is made of plastic.
 6. Theapparatus according to claim 2, wherein said first and second attachmentmeans are formed as a bayonet lock.
 7. The apparatus according to claim1, wherein said driving element of the drive unit is a reciprocatingelement adapted for said engagement to said reciprocable drive member bya coupling means.
 8. The apparatus according to claim 7, wherein saiddrive unit comprises an eccentric rotary shaft with a crank adapted toreciprocate said reciprocating element.
 9. The apparatus according toclaim 7, wherein said coupling means include a rod in one of saidreciprocating element and drive member, and a receptacle in the other ofsaid reciprocating element and drive member, said rod and saidreceptacle being adapted for locking to each other by a fastener,thereby providing said engagement.
 10. The apparatus according to claim9, wherein said fastener is a locking clip.
 11. The apparatus accordingto claim 9, wherein said rod constitutes a part of said reciprocabledrive member, and said receptacle constitutes a part of saidreciprocating element.
 12. The apparatus according to claim 9, whereinsaid rod is adapted to enter said receptacle during said attaching ofsaid pump unit to said drive unit, and is further adapted to be lockedby said fastener within one cycle of reciprocation.
 13. Pumpingapparatus, comprising a drive unit with a driving element, and a pumpunit attachable to and detachable from said drive unit, said pump unitincluding a pumping chamber and a pump member with a reciprocable drivemember, said pump member defining part of said pumping chamber, saidpumping chamber being adapted to expand and contract for pumping bytwo-way forced reciprocation of said pump member under action of saidreciprocable drive member; wherein said pump unit and said drive unitcomprise means for providing automatic engagement between said drivemember and said driving element responsive to said pump unit beingattached to said drive unit and said drive unit being in operation, saidengagement being reversible.
 14. Pumping apparatus, comprising a driveunit with a driving element, and a pump unit attachable to anddetachable from said drive unit, said pump unit including a pumpingchamber and a pump member with a reciprocable drive member, said pumpmember defining part of said pumping chamber, said pumping chamber beingadapted to expand and contract for pumping by two-way forcedreciprocation of said pump member under action of said recipro cabledrive member; wherein said pump unit and said drive unit comprise meansfor attaching said pump unit to said drive unit such as to bring saiddrive member and said driving element to a position wherein said drivemember is generally coaxial with said driving element, providing, duringoperation of said drive unit, for their engagement and reciprocation ofsaid drive member by means of said driving element; and wherein saidmeans for attaching said pump unit to said drive unit are configured forenabling tool free attachment of said pump unit to said drive unit.